Motor system detection device, vehicle and detection method
The phase voltage at the midpoint of the bridge arm is detected by a comparator and a level signal is output, which solves the problems of slow detection speed and low accuracy of the motor system and realizes real-time and accurate motor system detection.
Patent Information
- Application Number
- CN202410355189.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-26
- Publication Date
- 2025-09-26
AI Technical Summary
In the prior art, the motor system detection response speed is slow and there are errors in analog signal detection, which affects the detection accuracy.
A comparator is used to compare the phase voltages of the midpoints of the two bridge arms in the bridge arm group, and a first level signal is output. The controller performs motor system detection according to the level signal.
The response speed and accuracy of motor system detection are improved, analog signal acquisition errors are avoided, and real-time detection is achieved.
Smart Images
Figure CN120703560A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of motor technology, and in particular to a motor system detection device, a vehicle, and a detection method. Background Art
[0002] With the continuous development of social economy, cars have become an indispensable part of people's lives. New energy vehicles are equipped with many electronic devices. Any abnormality in each electronic device may cause the car to not operate normally. Therefore, existing new energy vehicles will detect the internal electronic devices so that the vehicle can enter a safe handling state in the event of an emergency or equipment failure to ensure the personal safety of vehicle users.
[0003] In existing technologies, for motor systems, vehicles typically compare bus voltage or bus current to determine whether the vehicle needs to enter a safe state. However, this method, which relies on analog signal detection, has a slow response speed and cannot detect the current operating status of the motor system in real time. Furthermore, the collected analog signals can contain significant errors, leading to errors in the comparison of bus voltage and bus current, thus affecting the accuracy of motor system detection. Summary of the Invention
[0004] In order to solve the above technical problems, the present disclosure provides a motor system detection device, a vehicle and a detection method to improve the response speed of motor system detection and the accuracy of motor system detection.
[0005] An embodiment of the present disclosure provides a motor system detection device, comprising: a controller and at least one comparator;
[0006] The two input terminals of the comparator are electrically connected to the midpoints of two bridge arms in a bridge arm group, respectively. The power module of the motor system includes a plurality of bridge arms, and any two of the bridge arms constitute a bridge arm group. The output terminal of the comparator is electrically connected to the input terminal of the controller.
[0007] The comparator is used for comparing the phase voltages at the midpoints of the bridge arms and then outputting a first level signal. The controller is used for detecting the motor system according to the first level signal.
[0008] Optionally, the motor system detection device includes a plurality of comparators, any group of the bridge arm groups is electrically connected to one comparator, and different bridge arm groups are electrically connected to different comparators.
[0009] Optionally, the power module includes a first bridge arm, a second bridge arm, and a third bridge arm connected in parallel, and the at least one comparator includes a first comparator, a second comparator, and a third comparator;
[0010] The first input end of the first comparator is electrically connected to the midpoint of the first bridge arm, and the second input end of the first comparator is electrically connected to the midpoint of the second bridge arm; the first input end of the second comparator is electrically connected to the midpoint of the second bridge arm, and the second input end of the second comparator is electrically connected to the midpoint of the third bridge arm; the first input end of the third comparator is electrically connected to the midpoint of the first bridge arm, and the second input end of the third comparator is electrically connected to the midpoint of the third bridge arm; the output end of the first comparator, the output end of the second comparator and the output end of the third comparator are all electrically connected to the input end of the controller.
[0011] Optionally, the motor system detection device further includes a drive detection unit;
[0012] The driving power supply of the motor system is electrically connected to the power supply end of the driving detection unit via a voltage stabilizer; the first input end of the driving detection unit is connected to a first reference signal, the second input end of the driving detection unit is connected to a second reference signal, and the output end of the driving detection unit is electrically connected to the input end of the controller; the first reference signal and the second reference signal are used to enable the driving detection unit to output a second level signal when the driving power supply is normal, and to enable the driving detection unit to output a third level signal when the driving power supply is abnormal, and the second level signal is different from the third level signal.
[0013] Optionally, the drive detection unit is an OR gate or a NOR gate, the motor system detection device further includes a first switch element and a second switch element, and the at least one comparator includes a fourth comparator and a fifth comparator;
[0014] The output end of the fourth comparator is electrically connected to the control end of the first switching element; the output end of the fifth comparator is electrically connected to the control end of the second switching element, the first end of the first switching element is electrically connected to the driving power supply, the second end of the first switching element and the first end of the second switching element are electrically connected to the first input end of the driving detection unit, and the second end of the second switching element and the second input end of the driving detection unit are grounded.
[0015] Optionally, the motor system detection device further includes a digital isolation chip, the output end of the comparator is electrically connected to the input end of the digital isolation chip, and the input end of the controller is electrically connected to the output end of the digital isolation chip.
[0016] An embodiment of the present disclosure also provides a vehicle, comprising a motor system and a motor system detection device as described above; the motor system comprises a power module, the power module comprises multiple bridge arms, and the two input ends of the comparator in the motor system detection device are electrically connected to the midpoints of the two bridge arms respectively.
[0017] The present disclosure also provides a motor system detection method, including:
[0018] Obtaining a first level signal output by a comparator, wherein the comparator is configured to compare two-phase voltages of a power module in the motor system and then output the first level signal;
[0019] The motor system is detected based on the first level signal.
[0020] Optionally, the detecting the motor system based on the first level signal includes:
[0021] determining the frequency of the phase voltage based on the first level signal when the motor of the motor system operates normally;
[0022] The actual rotational speed of the motor is calculated based on the frequency of the phase voltage.
[0023] Optionally, any two phase voltages of the power module are correspondingly connected to one comparator, and the method further includes:
[0024] If the level of the first level signal output by at least one of the comparators remains unchanged, determining that the motor is operating abnormally;
[0025] If the first level signal output by each comparator is a high-low level signal, it is determined that the motor operates normally.
[0026] Optionally, the method further includes:
[0027] Obtaining the level signal output by the drive detection unit;
[0028] If the level signal is a second level signal, it is determined that the driving power supply of the motor system is normal;
[0029] If the level signal is a third level signal, it is determined that the driving power supply of the motor system is abnormal.
[0030] Optionally, the method further includes:
[0031] In a case where the level signal is a second level signal, whether the actual rotation speed of the motor is the expected rotation speed is determined based on the duty cycle of the second level signal.
[0032] Optionally, the method further includes:
[0033] If the actual speed of the motor is higher than the expected speed, the upper arm switch or the lower arm switch of the power module is controlled to be disconnected;
[0034] If the actual rotation speed of the motor is lower than the expected rotation speed, all switches of the power module are controlled to be disconnected.
[0035] The technical solution provided by the embodiments of the present disclosure has the following advantages over the prior art:
[0036] In the solution provided by the embodiment of the present disclosure, the phase voltages at the midpoints of the two bridge arms in the bridge arm group are directly compared by using a comparator, and a first level signal is output based on the comparison result. The controller detects the motor system based on the first level signal to determine whether the motor system is abnormal and the abnormal situation of the motor system. Therefore, the present disclosure can convert the collected phase voltages at the midpoints of the bridge arms into a first level signal through the comparator, completing the conversion from analog signal to level signal. The controller only needs to detect the first level signal to complete the detection of the motor system, eliminating the tedious process of collecting, comparing and judging the phase voltages. In addition, the response speed of the level signal is faster than that of the analog signal, thereby improving the detection speed of the motor system and realizing real-time detection of the motor system. In addition, by detecting the level signal, it is also possible to avoid the large sampling error caused by the low accuracy of the acquisition of the analog signal, thereby causing the comparison result of the analog signal to be erroneous, making the detection accuracy of the motor system higher, thereby improving the accuracy of the detection of the motor system. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0038] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0039] Figure 1 A schematic diagram of a motor system detection device provided by an embodiment of the present disclosure;
[0040] Figure 2 A schematic diagram of another motor system detection device provided in an embodiment of the present disclosure;
[0041] Figure 3 A schematic diagram of another motor system detection device provided in an embodiment of the present disclosure;
[0042] Figure 4 A schematic diagram of a level signal provided in an embodiment of the present disclosure;
[0043] Figure 5 A flow chart of a motor system detection method provided in an embodiment of the present disclosure. DETAILED DESCRIPTION
[0044] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.
[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.
[0046] Figure 1 A schematic diagram of a motor system detection device provided by an embodiment of the present disclosure is shown in FIG. Figure 1 As shown, the motor system detection device includes: a controller 100 and at least one comparator 200 .
[0047] The two input terminals of the comparator 200 are respectively electrically connected to the midpoints of two bridge arms in a group of bridge arms. The power module 300 of the motor system includes multiple bridge arms, and any two bridge arms constitute a group of bridge arms. The output terminal 203 of the comparator 200 is electrically connected to the input terminal 101 of the controller 100.
[0048] The comparator 200 is used to compare the phase voltages at the midpoints of the bridge arms and then output a first level signal. The controller 100 is used to detect the motor system according to the first level signal.
[0049] Exemplarily, the first input terminal 201 of the comparator 200 is electrically connected to the first bridge arm 301 of the power module 300, and the second input terminal 202 of the comparator 200 is electrically connected to the second bridge arm 302 of the power module 300. The comparator 200 compares the phase voltage of the midpoint of the first bridge arm 301 of the power module 300 collected by the first input terminal 201 with the phase voltage of the midpoint of the second bridge arm 302 of the power module 300 collected by the second input terminal 202.
[0050] As the motor rotates, the voltage at the midpoint of the first bridge arm 301 of the power module 300 and the phase voltage at the midpoint of the second bridge arm 302 of the power module 300 change in real time, and the magnitude relationship between the two also changes accordingly. Therefore, the first level signal output by the comparator 200 also changes as the magnitude relationship between the two changes. For example, when the phase voltage at the midpoint of the first bridge arm 301 of the power module 300 is greater than the phase voltage at the midpoint of the second bridge arm 302 of the power module 300, the first level signal output by the comparator 200 is a high level signal; when the phase voltage at the midpoint of the first bridge arm 301 of the power module 300 is less than the phase voltage at the midpoint of the second bridge arm 302 of the power module 300, the first level signal output by the comparator 200 is a low level signal. The controller 100 will detect the received first level signal. When it is detected that the level signal of the first level signal remains unchanged, it is determined that the motor system is operating abnormally, and the abnormality of the motor system is checked at this time; when it is detected that the first level signal is a high and low level signal that changes periodically, it is determined that the motor system is operating normally, and the speed of the motor system continues to be detected.
[0051] The motor speed can be calculated using the following formula:
[0052]
[0053] Where N is the motor speed (unit: rpm), f is the frequency of the motor back EMF (unit: Hz), and P is the number of motor stages. The frequency of the motor back EMF is the waveform frequency of the phase voltage.
[0054] The waveform of the phase voltage generated by the motor during rotation is a sine wave. The phase voltage generated at the midpoint of the first bridge arm 301 of the power module 300 and the phase voltage generated at the midpoint of the second bridge arm 302 of the power module 300 have a phase difference of, for example, 120°. At this time, there is a time difference between the waveforms of the phase voltages received by the two output terminals of the comparator 200. The time when the comparator 200 outputs a high-level signal and the time when the comparator 200 outputs a low-level signal are both half the waveform period of the phase voltage. Therefore, it can be seen that the waveform period of the first-level signal output by the comparator 200 is the same as the waveform period of the phase voltage. Furthermore, it can be seen that the waveform frequency of the first-level signal output by the comparator 200 is equal to the waveform frequency of the phase voltage. Furthermore, since the motor's rotational speed can be calculated from the frequency of the phase voltage waveform using the above formula, the frequency of the first-level signal can be substituted into the above formula to calculate the motor speed. Thus, the controller can calculate the motor speed by processing the frequency of the first-level signal output by the comparator 200 and compare the calculated speed with the expected speed, thereby detecting the motor system speed using the first-level signal.
[0055] When the controller 100 detects that the motor system speed calculated from the acquisition is lower than the desired speed, the controller 100 controls the power module 300 to enter the freewheeling mode to increase the motor system speed to the desired speed. When the controller 100 detects that the motor system speed calculated from the acquisition is higher than the desired speed, the controller 100 controls the power module 300 to enter the ASC mode to reduce the motor system speed to the desired speed. Therefore, the present disclosure can also adjust the motor system speed by adjusting the power module 300 through the controller 100.
[0056] The embodiment of the present disclosure directly uses the comparator 200 to compare the phase voltages of the midpoints of the two bridge arms in the bridge arm group, and outputs a first level signal based on the comparison result. The controller 100 can then determine whether there is an abnormality in the working state of the motor system based on the first level signal. After eliminating the abnormality in the working of the motor system, the controller 100 can also calculate the speed of the motor system based on the frequency of the first level signal, compare the calculated speed with the expected speed, and determine whether there is an abnormality in the speed of the motor system based on the comparison result, thereby realizing the detection of the motor system. The present disclosure also converts the collected phase voltages of the midpoints of the bridge arms into a first level signal through the comparator 200, completing the conversion from analog signal to level signal. The controller 100 only needs to detect the first level signal to complete the detection of the motor system, eliminating multiple steps such as phase voltage collection, comparison and judgment, and the response speed of the level signal is faster than that of the analog signal, thereby improving the detection speed of the motor system and realizing real-time detection of the motor system. Moreover, by detecting the level signal, it is possible to avoid the large sampling error caused by the low sampling accuracy of the analog signal, which in turn causes errors in the comparison results of the analog signal, thereby making the detection accuracy of the motor system of this scheme higher and further improving the accuracy of the motor system detection.
[0057] In some embodiments, the motor system detection device includes a plurality of comparators, any group of bridge arm groups is electrically connected to one comparator, and different bridge arm groups are electrically connected to different comparators.
[0058] Exemplarily, there is a one-to-one correspondence between bridge arm groups and comparators, and the number of comparators is at least equal to the number of bridge arm groups, i.e., the combination number C(n, 2), where n is the number of bridge arms, for example, n is 3 or 4. In some embodiments, to accommodate each phase of the motor, the number of comparators can be determined by the number of bridge arms of the power module corresponding to the motor with the largest number of phases, i.e., the number of comparators satisfies the aforementioned combination number.
[0059] In some embodiments, Figure 2 A schematic diagram of another motor system detection device provided in an embodiment of the present disclosure is shown in FIG. Figure 2 As shown, the power module includes a first bridge arm 310 , a second bridge arm 320 and a third bridge arm 330 connected in parallel, and the at least one comparator includes a first comparator 210 , a second comparator 220 and a third comparator 230 .
[0060] The first input terminal 211 of the first comparator 210 is electrically connected to the bridge arm midpoint A of the first bridge arm 310, and the second input terminal 212 of the first comparator 210 is electrically connected to the bridge arm midpoint B of the second bridge arm 320; the first input terminal 221 of the second comparator 220 is electrically connected to the bridge arm midpoint B of the second bridge arm 320, and the second input terminal 222 of the second comparator 220 is electrically connected to the bridge arm midpoint C of the third bridge arm 330; the first input terminal 231 of the third comparator 230 is electrically connected to the bridge arm midpoint A of the first bridge arm 310, and the second input terminal 232 of the third comparator 230 is electrically connected to the bridge arm midpoint C of the third bridge arm 330; the output terminal 213 of the first comparator 210, the output terminal 223 of the second comparator 220 and the output terminal 233 of the third comparator 230 are all electrically connected to the input terminal of the controller 100.
[0061] Specifically, the power module further includes a first capacitor C1 and a power supply unit 340. The first ends of the first bridge arm 310, the second bridge arm 320, and the third bridge arm 330 are all electrically connected to the positive terminal of the power supply unit 340 and the first end of the first capacitor C1. The second ends of the first bridge arm 310, the second bridge arm 320, and the third bridge arm 330 are all electrically connected to the negative terminal of the power supply unit 340 and the second end of the first capacitor C1. The output terminal 213 of the first comparator 210 is electrically connected to the first input terminal 110 of the controller 100, the output terminal 223 of the second comparator 220 is electrically connected to the second input terminal 120 of the controller 100, and the output terminal 233 of the third comparator 230 is electrically connected to the third input terminal 130 of the controller 100. The voltage of the power supply unit 340 is provided by the bus voltage, and the first capacitor C1 is a bus capacitor.
[0062] The first comparator 210 collects and compares the phase voltage at the bridge arm midpoint A and the phase voltage at the bridge arm midpoint B. Based on the comparison results, it outputs a corresponding level signal to the controller 100. The controller 100 can determine whether the operating state of the motor system is abnormal by determining whether the level signal is a high or low level signal. The controller 100 also simultaneously determines the level signals output by the second comparator 220 and the third comparator 230. When the level signals output by the comparator are abnormal, it can be determined that the operating state of the motor system is abnormal. Since the speed of the motor system can be calculated by calculating the waveform frequency of the phase voltage, and the frequency of the level signal output by the first comparator 210 is the same as the waveform frequency of the phase voltage, the controller 100 can calculate the speed of the motor system by collecting the frequency of the level signal output by the first comparator 210. Similarly, the controller 100 can also calculate the speed of the motor system by the frequency of the level signal output by the second comparator 220 and the frequency of the level signal output by the third comparator 220. Therefore, the embodiment of the present disclosure compares the three-phase voltages of the motor system in pairs and outputs three level signals accordingly according to the comparison results. When the judgment of any one level signal is abnormal, the other level signals can also be judged. When the other level signals are also judged to be abnormal, it can be judged that the working state or speed of the motor system is abnormal. Therefore, the robustness of the controller in judging the abnormal working state and speed of the motor system can be improved, avoiding the situation where the controller 100 judges that the motor is abnormal due to an erroneous output of a comparator, and further improving the accuracy of detection.
[0063] For example, this embodiment of the present invention can also use two comparators to determine which phase of the motor system has a problem. Taking the first comparator 210 and the second comparator 220 as an example, when the controller determines that the level signal output by the first comparator 210 is a normal signal and the level signal output by the second comparator 220 is an abnormal signal. Since the first comparator 210 is electrically connected to the bridge arm midpoint A of the first bridge arm 310 and the bridge arm midpoint B of the second bridge arm 320, it can be determined that the phase voltages of the first bridge arm 310 and the second bridge arm 320 are normal. Since the second comparator 220 is electrically connected to the bridge arm midpoint B of the second bridge arm 320 and the bridge arm midpoint C of the third bridge arm 330, and since the first comparator 210 has determined that the phase voltage of the second bridge arm 320 is normal, it can be inferred that the phase voltage of the third bridge arm 330 is abnormal, thereby achieving accurate determination of the abnormal phase position of the motor system.
[0064] In some embodiments, see Figure 2The first bridge arm 310 includes a first switch unit 311 and a second switch unit 312 connected in series; the second bridge arm 320 includes a third switch unit 321 and a fourth switch unit 322 connected in series; and the third bridge arm 330 includes a fifth switch unit 331 and a sixth switch unit 332 connected in series. The control terminals of the first switch unit 311, the second switch unit 312, the third switch unit 321, the fourth switch unit 322, the fifth switch unit 331, and the sixth switch unit 332 are all electrically connected to the output terminal of the controller 100. The midpoint A of the first bridge arm 310 is located between the first switch unit 311 and the second switch unit 312, the midpoint B of the second bridge arm 320 is located between the third switch unit 321 and the fourth switch unit 322, and the midpoint C of the third bridge arm 330 is located between the fifth switch unit 331 and the sixth switch unit 332.
[0065] Specifically, the control ends of the first switch unit 311, the second switch unit 312, the third switch unit 321, the fourth switch unit 322, the fifth switch unit 331 and the sixth switch unit 332 are all electrically connected to the output end of the controller 100. When the controller 100 detects that the speed of the motor system obtained by the collection and calculation is lower than the expected speed, the controller 100 controls the first switch unit 311, the second switch unit 312, the third switch unit 321, the fourth switch unit 322, the fifth switch unit 331 and the sixth switch unit 332 to be turned off, so that the power module enters the freewheeling mode, thereby increasing the speed of the motor system and reaching the expected speed. When the controller 100 detects that the speed of the motor system obtained by the collection and calculation is higher than the expected speed, the controller 100 controls the first switch unit 311, the third switch unit 321 and the fifth switch unit 331, or the second switch unit 312, the fourth switch unit 322 and the sixth switch unit 332 to be turned off, so that the power module enters the ASC mode, thereby reducing the speed of the motor system and reaching the expected speed. Therefore, the present disclosure realizes the regulation of the speed of the motor system by turning on and off the first switch unit 311, the second switch unit 312, the third switch unit 321, the fourth switch unit 322, the fifth switch unit 331 and the sixth switch unit 332 through the controller 100.
[0066] In some embodiments, the first switch unit, the second switch unit, the third switch unit, the fourth switch unit, the fifth switch unit, and the sixth switch unit are all IGBTs.
[0067] In some embodiments, the motor system detection device further includes a drive detection unit.
[0068] The driving power supply of the motor system is electrically connected to the power supply end of the driving detection unit via a voltage stabilizer; the first input end of the driving detection unit is connected to a first reference signal, the second input end of the driving detection unit is connected to a second reference signal, and the output end of the driving detection unit is electrically connected to the input end of the controller; the first reference signal and the second reference signal are used to enable the driving detection unit to output a second level signal when the driving power supply is normal, and to enable the driving detection unit to output a third level signal when the driving power supply is abnormal, and the second level signal is different from the third level signal.
[0069] Among them, the voltage regulator can be a voltage regulator diode or a low voltage difference linear regulator. By setting the voltage regulator, the voltage output of the driving power supply can be guaranteed to be stable, avoiding overvoltage or undervoltage, and ensuring the normal operation of the motor system detection device.
[0070] Exemplarily, the motor system detection device includes two comparators, the output ends of the two comparators being electrically connected to the first input end and the second input end of the drive detection unit, respectively, to receive a first reference signal and a second reference signal outputted by the two comparators, wherein both the first reference signal and the second reference signal are level signals. When the drive power supply is normal, the drive detection unit outputs a second level signal that alternates between high and low levels based on the input first and second reference signals. When the drive power supply is abnormal, the drive detection unit cannot operate normally, and in this case, the drive detection unit outputs a third level signal whose level remains unchanged. Thus, the controller can determine whether the drive power supply is operating normally by determining whether the level outputted by the drive detection unit is a level signal that alternates between high and low levels. Furthermore, when the drive power supply is operating normally, the second level signal outputted by the drive detection unit is determined based on the first and second reference signals outputted by the comparators. Therefore, the duty cycle of the second level signal is affected by the frequencies of the first and second reference signals, and thus, the duty cycle of the second level signal is affected by the speed of the motor system. Therefore, after detecting the speed of the motor system, the duty cycle of the second-level signal can be compared with the expected duty cycle. When the duty cycle of the second-level signal is the same as the expected duty cycle, it can be determined that the speed meets the expected value, thereby verifying the speed detection. In addition, when the drive detection unit outputs the third-level signal, the controller determines that the drive power supply is abnormal and controls the power module to enter the ASC mode.
[0071] In some embodiments, Figure 3 A schematic diagram of another motor system detection device provided in an embodiment of the present disclosure is shown in FIG. Figure 3 As shown, the drive detection unit 410 is an OR gate or a NOR gate, the motor system detection device further includes a first switch element 420 and a second switch element 430 , and the at least one comparator includes a fourth comparator 240 and a fifth comparator 250 .
[0072] The output terminal 243 of the fourth comparator 240 is electrically connected to the control terminal 423 of the first switching element 420; the output terminal 253 of the fifth comparator 250 is electrically connected to the control terminal 433 of the second switching element 430, the first terminal 421 of the first switching element 420 is electrically connected to the driving power supply 500, the second terminal 422 of the first switching element 420 and the first terminal 431 of the second switching element 430 are electrically connected to the first input terminal 411 of the driving detection unit 410, and the second terminal 432 of the second switching element 430 and the second input terminal 412 of the driving detection unit 410 are grounded.
[0073] Exemplarily, the power module 300 includes a first bridge arm 301, a second bridge arm 302 and a third bridge arm 303, the driving power supply 500 is electrically connected to the power supply end 414 of the driving detection unit 410 through the voltage regulator 600, the first input end 241 of the fourth comparator 240 is electrically connected to the midpoint of the bridge arm of the first bridge arm 301, the second input end 242 of the fourth comparator 240 is electrically connected to the midpoint of the bridge arm of the second bridge arm 302, the first input end 251 of the fifth comparator 250 is electrically connected to the midpoint of the bridge arm of the second bridge arm 302, the second input end 252 of the fifth comparator 250 is electrically connected to the midpoint of the bridge arm of the third bridge arm 303, and the voltage output by the driving power supply 500 through the voltage regulator 600 is V.
[0074] Figure 4 A schematic diagram of a level signal provided by an embodiment of the present disclosure is shown in FIG. Figure 4 As shown, the first reference signal S1 output by the fourth comparator 240 and the second reference signal S2 output by the fifth comparator 250 are both high and low level signals and have a phase difference. For example, the first switch element 420 and the second switch element 430 are NMOS transistors, and the drive detection unit 410 is an OR gate.
[0075] When the output voltage of the driving power supply 500 is normal, within a time period, when the second reference signal S2 is a high-level signal, since the first reference signal S1 and the second reference signal S2 have a phase difference, the first reference signal S1 remains a low-level signal within a period of time T1. During the time T1, the first switching element 420 is turned off and the second switching element 430 is turned on. The first input terminal 411 of the driving detection unit 410 receives the signal S3 which is a high-level signal with a magnitude of V / 2. The second input terminal 512 of the driving detection unit 410 is grounded, and the S4 signal output by the driving detection unit 410 within the time T1 is a high-level signal.
[0076] At the beginning of the next time T2, the first reference signal S1 and the second reference signal S2 are both high-level signals. During the time T2, the first switch element 420 and the second switch element 430 are both turned on. The first input terminal 411 of the drive detection unit 410 receives the signal S3 which is a high-level signal with a magnitude of V. The second input terminal 512 of the drive detection unit 410 is grounded, and the S4 signal output by the drive detection unit 410 during the time T2 is a high-level signal.
[0077] At the beginning of the next time T3, the first reference signal S1 is a high-level signal, and the second reference signal S2 becomes a low-level signal. During the time T3, the first switching element 420 is turned on, and the second switching element 430 is turned off. The first input terminal 411 of the driving detection unit 410 receives the signal S3 which is a high-level signal with a magnitude of V / 2. The second input terminal 512 of the driving detection unit 410 is grounded, and the S4 signal output by the driving detection unit 410 during the time T3 is a high-level signal.
[0078] At the beginning of the next time T4, the first reference signal S1 and the second reference signal S2 are both low-level signals. During the time T2, the first switch element 420 and the second switch element 430 are both turned off, and there is no signal at the first input terminal 411 of the driving detection unit 410. Then, the S4 signal output by the driving detection unit 410 during the time T4 is a low-level signal.
[0079] When the output voltage of the driving power supply 500 is abnormal, the power supply end of the driving detection unit 410 is de-energized, and the driving detection unit 410 stops operating. At this time, the level signal received by the controller 100 from the driving detection unit 410 is a normally high level signal or no output signal. When the output voltage of the driving power supply 500 is normal, the controller 100 can receive a level signal from the driving detection unit 410 that alternates between high and low levels. Thus, the controller 100 can determine whether there is an abnormality in the operation of the driving power supply 500 based on the signal output by the driving detection unit 410. Furthermore, when the driving power supply 500 is operating normally, the level signal S4 output by the driving detection unit 410 is determined based on the first reference signal S1 and the second reference signal S2 output by the comparator. Therefore, the duty cycle of the level signal S4 is affected by the frequencies of the first reference signal S1 and the second reference signal S2. Furthermore, it can be seen that the duty cycle of the level signal S4 is affected by the speed of the motor system. Therefore, after detecting the speed of the motor system, the duty cycle of the level signal S4 can be compared with the expected duty cycle. When the duty cycle of the level signal S4 is the same as the expected duty cycle, it can be determined that the speed meets the expected value, thereby realizing verification of the speed detection.
[0080] In some embodiments, see Figure 2 and Figure 3The motor system detection device further includes a digital isolation chip 700 , the output end of the comparator is electrically connected to the input end of the digital isolation chip 700 , and the input end of the controller 100 is electrically connected to the output end of the digital isolation chip 700 .
[0081] Specifically, the output end of each comparator is electrically connected to the controller 100 through the digital isolation chip 700. The digital isolation chip 700 can amplify or reduce each received signal to ensure the consistency of the input and output signals, and to ensure that there is no interference between the signals, thereby enhancing the accuracy of the motor system detection.
[0082] An embodiment of the present disclosure also provides a vehicle, including a motor system and a motor system detection device as described above; the motor system includes a power module, the power module includes multiple bridge arms, and the two input ends of the comparator in the motor system detection device are electrically connected to the midpoints of the two bridge arms respectively.
[0083] The vehicle disclosed in the above embodiment has the same or corresponding beneficial effects as the motor system detection device disclosed in the above embodiments, and will not be described again here to avoid repetition.
[0084] Figure 5 This is a flow chart of a motor system detection method provided by an embodiment of the present disclosure. The motor system detection method includes: S810 and S820.
[0085] S810: Obtain a first level signal output by a comparator.
[0086] Specifically, the comparator is used to compare the two-phase voltages of the power module in the motor system and then output a first level signal.
[0087] S820: Detect the motor system based on the first level signal.
[0088] Specifically, during motor rotation, the phase voltages at the midpoints of each bridge arm of the power module change in real time, and the magnitude relationship between the phase voltages also changes accordingly. Therefore, the first-level signal output by the comparator also changes with the change in the magnitude relationship of the phase voltages. For example, when the phase voltage input to the first input of the comparator is greater than the phase voltage input to the second input of the comparator, the first-level signal output by the comparator is a high-level signal; when the phase voltage input to the first input of the comparator is less than the phase voltage input to the second input of the comparator, the first-level signal output by the comparator is a low-level signal. The controller obtains the first-level signal output by the comparator and detects the received first-level signal. If the first-level signal is detected to remain unchanged, it determines that the motor system is operating abnormally; if the first-level signal is detected to be a periodically changing high and low-level signal, it determines that the motor system is operating normally.
[0089] The embodiment of the present disclosure directly uses a comparator to compare the phase voltages of the bridge arm midpoints of each bridge arm in the bridge arm group, and outputs a first level signal based on the comparison result. The controller can then determine whether there is an abnormality in the working state of the motor system based on the first level signal, thereby realizing the detection of the motor system. The present disclosure also converts the collected phase voltages of the bridge arm midpoints into a first level signal through a comparator, completing the conversion from an analog signal to a level signal. The controller only needs to detect the first level signal to complete the detection of the motor system, eliminating multiple steps such as the acquisition, comparison, and judgment of the phase voltage, and the response speed of the level signal is faster than that of the analog signal, thereby improving the detection speed of the motor system and realizing real-time detection of the motor system. In addition, by detecting the level signal, it is also possible to avoid the large sampling error caused by the low sampling accuracy of the analog signal, which in turn causes the analog signal comparison result to be erroneous, making the detection accuracy of the motor system of this solution higher, further improving the accuracy of the motor system detection.
[0090] In some embodiments, detecting the motor system based on the first level signal includes: determining the frequency of the phase voltage based on the first level signal when the motor of the motor system operates normally.
[0091] Based on the frequency of the phase voltage, the actual speed of the motor is calculated.
[0092] It should be noted that when it is determined that the motor of the motor system is operating normally, the motor speed is detected again. The detection of abnormal operation of the motor system can be the detection method provided in the embodiment of the present disclosure, or it can be other detection methods other than the embodiment of the present disclosure, and no specific limitation is made here.
[0093] For example, the motor speed can be calculated using the following formula:
[0094]
[0095] Where N is the motor speed (unit: rpm), f is the frequency of the motor back EMF (unit: Hz), and P is the number of motor stages. The frequency of the motor back EMF is the waveform frequency of the phase voltage.
[0096] The waveform of the phase voltage generated by the motor during rotation is a sine wave. There is a phase difference between the phase voltages at the midpoints of the bridge arms of each bridge arm. Therefore, the time when the two input terminals of the comparator receive phase voltages of the same voltage magnitude is also different. At this time, the time when the comparator outputs a high-level signal and the time when the comparator outputs a low-level signal are both half of the waveform period of the phase voltage. It can be seen from this that the waveform period of the first-level signal output by the comparator is the same as the waveform period of the phase voltage, and it can be further known that the waveform frequency of the first-level signal output by the comparator is equal to the waveform frequency of the phase voltage. Since the rotation speed of the motor can be calculated by the frequency of the phase voltage waveform using the above formula, the frequency of the first-level signal can be substituted into the above formula to calculate the motor speed. Therefore, the controller can obtain the frequency of the phase voltage through the evaluation of the first-level signal, and then calculate the actual speed of the motor.
[0097] In some embodiments, any two phase voltages of the power module are connected to a corresponding comparator, and the method further includes: if the level of the first level signal output by at least one comparator remains unchanged, determining that the motor is operating abnormally.
[0098] If the first level signals output by each comparator are high-level and low-level signals, it is determined that the motor operates normally.
[0099] Exemplarily, the power module includes three bridge arms, and any two-phase voltages at the midpoints of the three bridge arms are compared in pairs. Therefore, three comparators can be provided. Since the phase voltages at the midpoints of the three bridge arms change with the rotation of the motor, the magnitude relationship between the two phase voltages input to the two input terminals of the comparator also changes accordingly. The comparator then outputs a first level signal that alternates between high and low levels as the magnitude relationship between the two phase voltages changes. Therefore, normal motor operation can only be determined when the first level signal is high and low. If the first level signal remains unchanged, abnormal motor operation can be determined. Furthermore, since the three comparators compare any two of the three-phase voltages of the power module, three level signals are output based on the comparison results. If any one level signal is abnormal, the other level signals can also be determined. If the other level signals are also abnormal, abnormal motor operation or speed can be determined. This improves the robustness of the controller in determining abnormal motor operation and speed, avoiding situations where the controller determines a motor abnormality due to an erroneous comparator output, further improving detection accuracy.
[0100] In some embodiments, the motor system detection method further includes: acquiring a level signal output by the drive detection unit, and if the level signal is a second level signal, determining that the drive power supply of the motor system is normal.
[0101] If the level signal is the third level signal, it is determined that the driving power supply of the motor system is abnormal.
[0102] Specifically, the motor system also includes a drive detection unit and two comparators, the output ends of the two comparators are electrically connected to the first input end and the second input end of the drive detection unit, respectively, to receive a first reference signal and a second reference signal output from the two comparators, and the first reference signal and the second reference signal are both level signals. When the drive power supply is normal, the drive detection unit outputs a second level signal that alternates between high and low levels based on the input first reference signal and the second reference signal; when the drive power supply is abnormal, the drive detection unit cannot work normally, and the drive detection unit outputs a third level signal whose level remains unchanged. Thus, the controller can determine whether the drive power supply is working normally by checking whether the level output by the drive detection unit is a level signal that alternates between high and low levels. If the level signal is a second level signal that alternates between high and low levels, it is determined that the drive power supply of the motor system is normal; if the level signal is a third level signal that remains unchanged, it is determined that the drive power supply of the motor system is abnormal.
[0103] In some embodiments, the motor system detection method further includes: when the level signal is a second level signal, determining whether the actual speed of the motor is the expected speed based on a duty cycle of the second level signal.
[0104] Specifically, when the driving power supply is operating normally, the level signal output by the driving detection unit is a second level signal. The second level signal output by the driving detection unit is determined based on the first reference signal and the second reference signal output by the comparator. Therefore, the duty cycle of the second level signal is affected by the frequency of the first reference signal and the second reference signal. It can be seen that the duty cycle of the second level signal is affected by the speed of the motor system. Therefore, after detecting the speed of the motor system, the duty cycle of the second level signal can also be compared with the expected duty cycle. When the duty cycle of the second level signal is the same as the expected duty cycle, it can be determined that the speed meets the expected value, thereby realizing the verification of the speed detection.
[0105] In some embodiments, the motor system detection method further includes: if the actual speed of the motor is higher than the expected speed, controlling the upper arm switch or the lower arm switch of the power module to be disconnected.
[0106] If the actual speed of the motor is lower than the expected speed, all switches of the power module are controlled to be disconnected.
[0107] Specifically, when the controller detects that the actual speed of the motor is lower than the desired speed, the controller controls all switches in the power module to disconnect, and the power module enters freewheeling mode, thereby increasing the speed of the motor system to the desired speed. When the controller detects that the speed of the motor system obtained by acquisition and calculation is higher than the desired speed, the controller controls the upper bridge arm switch or the lower bridge arm switch of the power module to disconnect, and the power module enters ASC mode, thereby reducing the speed of the motor system to the desired speed. Therefore, the present disclosure can also achieve regulation of the motor system speed by controlling the on and off of switches in the power module through the controller.
[0108] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.
[0109] The above are merely specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to these embodiments, but is to be construed in the broadest manner consistent with the principles and novel features disclosed herein.
Claims
1. A motor system detection device, characterized in that: include: a controller and at least one comparator; The two input terminals of the comparator are electrically connected to the midpoints of two bridge arms in a bridge arm group, respectively. The power module of the motor system includes a plurality of bridge arms, and any two of the bridge arms constitute a bridge arm group. The output terminal of the comparator is electrically connected to the input terminal of the controller. The comparator is used for comparing the phase voltages at the midpoints of the bridge arms and then outputting a first level signal. The controller is used for detecting the motor system according to the first level signal.
2. The motor system detection device according to claim 1, characterized in that: The motor system detection device includes a plurality of comparators, any group of the bridge arm groups is electrically connected to one comparator, and different bridge arm groups are electrically connected to different comparators.
3. The motor system detection device according to claim 2, characterized in that: The power module includes a first bridge arm, a second bridge arm, and a third bridge arm connected in parallel, and the at least one comparator includes a first comparator, a second comparator, and a third comparator; The first input end of the first comparator is electrically connected to the midpoint of the first bridge arm, and the second input end of the first comparator is electrically connected to the midpoint of the second bridge arm; the first input end of the second comparator is electrically connected to the midpoint of the second bridge arm, and the second input end of the second comparator is electrically connected to the midpoint of the third bridge arm; the first input end of the third comparator is electrically connected to the midpoint of the first bridge arm, and the second input end of the third comparator is electrically connected to the midpoint of the third bridge arm; the output end of the first comparator, the output end of the second comparator and the output end of the third comparator are all electrically connected to the input end of the controller.
4. The motor system detection device according to claim 1, characterized in that: The motor system detection device further includes a drive detection unit; The driving power supply of the motor system is electrically connected to the power supply terminal of the driving detection unit via a voltage stabilizer; the first input terminal of the driving detection unit is connected to a first reference signal, the second input terminal of the driving detection unit is connected to a second reference signal, and the output terminal of the driving detection unit is electrically connected to the input terminal of the controller; The first reference signal and the second reference signal are used to enable the drive detection unit to output a second level signal when the drive power supply is normal, and to enable the drive detection unit to output a third level signal when the drive power supply is abnormal, wherein the second level signal is different from the third level signal.
5. The motor system detection device according to claim 4, characterized in that: The drive detection unit is an OR gate or a NOR gate, the motor system detection device further includes a first switch element and a second switch element, and the at least one comparator includes a fourth comparator and a fifth comparator; The output end of the fourth comparator is electrically connected to the control end of the first switching element; the output end of the fifth comparator is electrically connected to the control end of the second switching element, the first end of the first switching element is electrically connected to the driving power supply, the second end of the first switching element and the first end of the second switching element are electrically connected to the first input end of the driving detection unit, and the second end of the second switching element and the second input end of the driving detection unit are grounded.
6. The motor system detection device according to any one of claims 1 to 5, characterized in that: The motor system detection device further includes a digital isolation chip, the output end of the comparator is electrically connected to the input end of the digital isolation chip, and the input end of the controller is electrically connected to the output end of the digital isolation chip.
7. A vehicle, characterized in that: It comprises a motor system and a motor system detection device as described in any one of claims 1 to 6; the motor system comprises a power module, the power module comprises a plurality of bridge arms, and the two input ends of the comparator in the motor system detection device are electrically connected to the midpoints of the two bridge arms respectively.
8. A motor system detection method, characterized in that: include: Obtaining a first level signal output by a comparator, wherein the comparator is configured to compare two-phase voltages of a power module in the motor system and then output the first level signal; The motor system is detected based on the first level signal.
9. The motor system detection method according to claim 8, characterized in that: The detecting the motor system based on the first level signal includes: determining the frequency of the phase voltage based on the first level signal when the motor of the motor system operates normally; The actual rotational speed of the motor is calculated based on the frequency of the phase voltage.
10. The motor system detection method according to claim 8, characterized in that: Any two phase voltages of the power module are correspondingly connected to one comparator, and the method further includes: If the level of the first level signal output by at least one of the comparators remains unchanged, determining that the motor is operating abnormally; If the first level signal output by each comparator is a high-low level signal, it is determined that the motor operates normally.
11. The motor system detection method according to claim 8, characterized in that: The method further comprises: Obtaining the level signal output by the drive detection unit; If the level signal is a second level signal, it is determined that the driving power supply of the motor system is normal; If the level signal is a third level signal, it is determined that the driving power supply of the motor system is abnormal.
12. The motor system detection method according to claim 11, characterized in that: The method further comprises: In a case where the level signal is a second level signal, whether the actual rotation speed of the motor is the expected rotation speed is determined based on the duty cycle of the second level signal.
13. The motor system detection method according to claim 9, characterized in that: The method further comprises: If the actual speed of the motor is higher than the expected speed, the upper arm switch or the lower arm switch of the power module is controlled to be disconnected; If the actual rotation speed of the motor is lower than the expected rotation speed, all switches of the power module are controlled to be disconnected.